Antennae elongate, robust especially in male, up to two-thirds of the body length, sparsely setose; antenna 1 flagellum up to about 18-articulate; antenna 2 in male longer than antenna 1 and very robust, flagellum about 11-articulate; antenna 2 in female equal to the length of antenna 1, flagellum only about 7-articulate. Gnathopod 1 basis narrow proximally and with a pronounced anterodistal lobe, propodus rectangular, palm oblique delimited by a large spine. Female gnathopod 2 larger than gnathopod 1, basis and ischium with a distinct anterodistal lobe, propodus oval, palm oblique, convex, delimited by a large spine. Male gnathopod 2 very large and robust, basis and ischium with a large anterodistal lobe, carpus with a narrow posterior lobe and with the anterior margin spinose, propodus broad, swollen proximally and flattened distally especially in larger specimens, palm oblique, straight, delimited by a quadrate angle and submarginal spine. Pereiopod 5 basis moderately expanded but longer than wide; pereiopods 5 to 7 propodus strongly expanded distally producing a subchelate closure with the dactylus, palm with three or four graduated spines and a single large curved spine. Uropod 3 inner ramus setose, outer ramus with two large curved spines. Telson with a pair of large curved distolateral hooks and several short setae.
Up to about 8 mm.
Intertidal and shallow subtidal amongst algae.
Bohuslän, North Sea, west and northern Norway to the English Channel.